I have just read your article about the multitude of beeps regarding seatbelts and open doors. You suggested turning the vehicles off when stopped at the ATM, or generally when in line (like Tim Horton's drive-thru). I vaguely recall data that most engine wear (something like 60 per cent) occurs during startup, mostly because of a lack of oil due to gravity drainage and the time it takes to fully start circulation. Is this still a concern on modern engines? Obviously there is less drainage when the engine is off for 30 seconds, rather than overnight. Is there a substantial increase in wear with winter temperatures? Is there any rule of thumb on idle time, turn it off? For instance, the line at Tim Horton's moves fairly quickly, so I would only be waiting a few seconds before I have to turn it on and move forward again. I know that hybrid engines do this stuff automatically, but I don't think my non-hybrid had this constant stop-start of the engine in the design plans. – Kevin in Calgary
As a rule of thumb you can, and should, shut your engine off if idling more than 30 seconds or so.
The two general concerns are the ability to restart and, less significantly, lubrication. Let's deal with that one first. Modern oils are so much more sophisticated than used to be the case that lubrication, if sitting for less than say several months, is not a problem. The additives in modern oils and the tight tolerances in current engines makes drainage pretty much a non-issue.
As for winter, once again the modern multi-weight blends and additives do a good job of ensuring coverage when off and quick circulation upon startup.
As to the issue of restarting an engine repeatedly, a normal engine/starter combination should be able to handle this for several occasions close together. Today's engines, with precise fuel injection and electronically controlled ignitions, fire very quickly, without causing the battery to turn over the starter more than once or twice.
However, doing so too often without giving the starter time to cool and the battery to recharge could be a problem.
We are going to see a great deal more of what is called start-stop technology in the next few years as manufacturers look for ways to increase fuel mileage and reduce exhaust emissions. Systems that automatically stop an engine when the vehicle sits and restart it instantly are ready to go as soon as government-mandated testing and economy rating procedures are updated to recognize the resulting improvements in mileage and emissions.
Virtually all hybrids use start-stop as they have a big electric motor that can double as a starter. Mazda has developed a slick system that uses engine compression, instead of the starter, to restart. Others will be along.